Note that because tableevents that set the
acl2-defaults-table are implicitly local,
set-enforce-redundancy events are ignored when including books. However,
the presence of the event (set-enforce-redundancy t) in a book guarantees
that its subsequent definitions and theorems are redundant. This can be a
useful property to maintain in library development, as we now describe.

An example of the use of this form can be found in the distributed books
under directory books/rtl/rel4/. The intention in that directory has
been to put all the gory details in subdirectories support/ and
arithmetic/, so that the books in subdirectory lib/ contain only the
``exported'' definitions and theorems. This approach is useful for human
readability. Moreover, suppose we want to prove new theorems in lib/.
Typically we wish to prove the new theorems using the existing books in
lib/; however, our methodology demands that the proofs go into books in
support/. If every theorem in lib/ is redundant, then we can
develop the proofs in lib/ but then when we are done, move each
book with such proofs into support/ as follows. In any such book, we
first replace include-book forms referring to books in lib/ by
include-book forms referring to corresponding books in support/
and/or arithmetic/. Then, we add suitable in-theory events to get
us back into the original lib/ proof environment.

The default behavior of the system is as though the :enforce-redundancy
value is nil. The current behavior can be ascertained by evaluating the
following form.